Telescoping passages in a string have been used for production or injection. The passages in the telescoping members are initially closed so that internal pressure in the string can be developed to power out the telescoping members against the formation. In some application, the extended members against the formation provide the conduit for flow after a cement job fills the annular space around the extended members. In open hole completions the passages in the telescoping members can also have a sand control feature such as a bead pack that traps solids as the passages are put in service in a production mode.
In order to extend the telescoping members the blocking agent used was biodegradable polyvinyl alcohol that was applied to a bead pack. The material provided a seal long enough to be able to move the telescoping members out to the formation. Eventually the material disappeared such as by melting or dissolving and the passage was then opened with the telescoping assemblies extended so that the bead pack in the passage was now exposed and ready to function as a sand control device. In order to allow enough time to deploy the string and extend the telescoping members the disappearing time would be set to take days. In some instances particular fluids had to be introduced to initiate the disappearing of the plug.
Disappearing plugs have been used in zone isolation as illustrated in U.S. Pat. Nos. 7,395,856 and 7,552,779. Telescoping members with a sand control feature are illustrated in U.S. Pat. Nos. 7,475,729 and 7,604,055. The following patents show a telescoping assembly with a barrier used to extend the members and how the barrier is then removed: U.S. Pat. Nos. 5,829,520; 7,316,274 and 7,591,312. Swelling materials such as shape memory foam are illustrated to function as an annularly shaped screen in a downhole application in U.S. Pat. Nos. 7,318,481 and 7,013,979.
The present invention replaces the blocking material that allows pressure to extend the telescoping elements with a shape memory foam that is compressed at above its critical temperature to an extent that it is effectively impervious. It is mounted in the passage of the telescoping assemblies and allows them to be extended under pressure in the string. After extension and exposure to well fluids the critical temperature is crossed and the foam reverts to its original shape before its temperature was initially elevated. In that reverting condition the foam becomes porous and serves as a sand control barrier. The foam is constrained to enlarge in an axial direction by the telescoping assembly. Porous end supports can be optionally used to hold the foam in position against the force of flow going through the foam. In essence the foam in one state acts as a plug for extension of the telescoping member and in the second state serves as a sand or other debris excluder from production. Those and other aspects of the present invention can be better understood by those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while understanding that the full scope of the invention is to be determined by the appended claims.